(Sharecast News) - AG Barr's first half profit rose as the maker of Irn-Bru and other soft drinks steered a course through a soft drinks market made unpredictable by extreme weather and the introduction of the sugar tax. Pre-tax profit before exceptional items in the six months to the end of July rose 4% to £18.2m as revenue increased 5.5% to £136.9m. The FTSE 250 company upped its interim dividend by 5% to 3.90p.The Cumbernauld, Scotland-based company said the first half featured extreme wintry weather in March followed by a long summer heatwave that boosted sales, a shortage of carbon dioxide for fizzy drinks and the introduction of the soft drinks levy, also known as the sugar tax.AG Barr introduced a new lower-sugar recipe for Irn-Bru, its top selling brand, before the introduction of the sugar tax in April. It also introduced Irn-Bru Xtra, a sugarless version of the product, which is Scotland's best-selling soft drink and ranks third in the UK behind Coca-Cola and Pepsi.Roger White, AG Barr's chief executive, said the company, which also produces Funkin and Strathmore mineral water, was on track to meet full-year expectations.White said: "We have delivered a solid financial performance in the first half of the financial year, navigating through the soft drinks industry levy implementation, reformulation, extremes of weather and CO2 shortages in addition to a dynamic consumer, customer and macro-economic environment. Our core brands have performed well and have good momentum with both consumers and trade customers."Statutory pre-tax profit fell to £18.2m from £19.4m the year before when the company posted a £2.5m one-off gain from selling property. AG Barr shares, up 11% in 2018, fell 1.1% to 722p at 08:19 BST.